Definition of osteoarthritis on MRI: results of a Delphi exercise

Abstract

summary Objective Despite a growing body of Magnetic Resonance Imaging (MRI) literature in osteoarthritis (OA), there is little uniformity in its diagnostic application. We envisage in the first instance the definition requiring further validation and testing in the research setting before considering implementation/feasibility testing in the clinical setting. The objective of our research was to develop an MRI definition of structural OA. Methods We undertook a multistage process consisting of a number of different steps. The intent was to develop testable definitions of OA (knee, hip and/or hand) on MRI. This was an evidence driven approach with results of a systematic review provided to the group prior to a Delphi exercise. Each participant of the steering group was allowed to submit independently up to five propositions related to key aspects in MRI diagnosis of knee OA. The steering group then participated in a Delphi exercise to reach consensus on which propositions we would recommend for a definition of structural OA on MRI. For each round of voting, ≥60% votes led to include and ≥20% votes led to exclude a proposition. After developing the proposition one of the definitions developed was tested for its validity against radiographic OA in an extant database. Results For the systematic review we identified 25 studies which met all of our inclusion criteria and contained relevant diagnostic measure and performance data. At the completion of the Delphi voting exercise 11 propositions were accepted for definition of structural OA on MRI. We assessed the diagnostic performance of the tibiofemoral MRI definition against a radiographic reference standard. The diagnostic performance for individual features was: osteophyte C statistic = 0.61, for cartilage loss C statistic = 0.73, for bone marrow lesions C statistic= 0.72 and for meniscus tear in any region C statistic = 0.78. The overall composite model for these four features was a C statistic = 0.59. We detected good specificity (1) but less optimal sensitivity (0.46) likely due to detection of disease earlier on MRI. Conclusion We have developed MRI definition of knee OA that requires further formal testing with regards their diagnostic performance (especially in datasets of persons with early disease), before they are more widely used. Our current analysis suggests that further testing should focus on comparisons other than the radiograph, that may capture later stage disease and thus nullify the potential for detecting early disease that MRI may afford. The propositions are not to detract from, nor to discourage the use of traditional means of diagnosing OA.

Knee arthroscopies: who gets them, what does the radiologist report, and what does the surgeon find?

“…MRIs of the knee were classified as OA if the radiologist reported: Full joint space narrowing and osteophytes, or 1 of these in combination with 2 of the following features as suggested by Osteoarthritis Research Society International (OARSI) (Hunter et al 2011):…”

Defining knee pain trajectories in early symptomatic knee osteoarthritis in primary care: 5-year results from a nationwide prospective cohort study (CHECK)

“…[4][5][6] Numerous studies have determined risk factors for incident and radiographic progression of knee OA, but previous reviews have shown that only few studies have used symptomatic knee OA progression as an outcome measure. 7,8 Discordance remains in the apparent correlation between stages of knee OA assessed by clinical and radiographic criteria and pain severity.…”

Measuring Disease Progression in Osteoarthritis

“…Based on a systematic review of 25 MRI studies [44], tibiofemoral OA is currently defined as requiring a combination of features: either an osteophyte and full thickness cartilage loss or an osteophyte or full thickness cartilage loss, plus two or more of the following features: bone marrow lesion (BML) or cyst not associated with meniscal or ligamentous attachments, meniscal pathology, partial thickness cartilage loss (in the absence of full thickness cartilage loss), or bone attrition. Patellofemoral OA requires an osteophyte and partial or full thickness cartilage loss, all in the patella and/or anterior femur regions [44].…”

“…Patellofemoral OA requires an osteophyte and partial or full thickness cartilage loss, all in the patella and/or anterior femur regions [44]. MRI-based scoring systems have also been proposed in hand OA [45], a refinement of the Oslo hand OA scoring system, including osteophytes, JSN, bone erosions/attrition, cysts, malalignment, synovitis and BML in the distal and proximal interphalangeal (PIP) joints.…”